A perceptual study of the influence of pitch on the intelligibility of sung vowels.

A perceptual study of the influence of pitch on the intelligibility of vowels was carried out using a corpus containing all 15 French vowels sung by a professional soprano across her entire voice range. Four untrained subjects underwent identification tests whose results show statistically that vowel intelligibility is inversely proportional to pitch. A perceptual analysis based on confusion matrices revealed that intelligibility drops rapidly starting at the middle register. Classification of the confusions showed that incorrectly identified vowels tend to be confused with [a], most certainly because the shape of the vocal tract when in the upper register corresponds to that of the vowel [a].